This invention relates to a monitor apparatus located in the return grain elevator of a combine for monitoring the amount of grain being returned to the sorting sieves.
In grain combines, the grain and other material that does not pass through the sieves in the normal manner is called "tailings". These tailings are shunted out of the normal path and moved upward through a return grain elevator. At the upper end of the return grain elevator, chaff and grain fall out through an opening, pass through a chute, and then enter a return grain cross auger. Grain in this path eventually reenters the sieves to be sorted once again to recover grain that was not sorted out by the sieve, during the first pass over the sieves.
Heavy grain flow in the return grain cross auger path indicates to an operator that the combine sieves are closed too much. Light grain flow indicates that the sieves are open too far. With most combines, the only way an operator can check for excessive light grain flow in this path is to get out of the combine cab and go back and visually inspect the grain flow in either the return grain elevator or in the return grain cross auger.
Several patents have described electronic sensors placed on combines to help in the monitoring of grain flows. For example, see U.S. Pat. No. 4,036,065 to Strelioff et al. which describes the use of a microphone located at the rear of the sieves to determine by a sampling process the amount of grain lost over the back of the sieves and over the straw walker assembly. The microphone detects the sound of grain striking spaced apart fingers located adjacent to the rear end of the sieve.
U.S. Pat. No. 5,312,299 to Behnke et al. describes a grain flow measuring device utilizing a piezoelectric oscillator to gather a statistical sampling of grain from the trailing end of a rocker tray to measure the grain loss during the combining process. The piezoelectric oscillator is located behind a sensor plate against which grain strikes. The pressure of the grain striking the plate is detected by the piezoelectric oscillator.
Another piezoelectric grain flow monitor is shown in U.S. Pat. No. 3,606,745 to Girodat.
U.S. Pat. No. 4,441,513 to Herwig describes a photo-electric beam apparatus for sensing the total volume of trailings including both grain and chaff being returned by a grain return elevator.
It is an object of the present invention to provide a return grain elevator monitor located in the return grain path to detect the amount of grain that is being returned by the return grain elevator so that the sieves in the normal grain flow path can be adjusted accordingly.